X-ray apparatus



May 12, 1936. A H B. MGEUEN x-RAY APPARATUS Filed Feb. 15A 195o 2 sheets-sheet 1 NN AQ anode,A is, as a result into heat forv which no Patented May .12, 1936 UNITED STATES PATENT oFFlcE 2,040,441 X-RAY APPARATUS Harry McEuen, Jacksonville, Fla. Application February 15, 1930, Serial No. 428,798 14 Claims. (Cl. Z50-34) The invention is directed to an improvement in rent in the face oi' insuilcient heat dissipatin' or diiusion, the tube is very liable to be damaged. 'I'he present type of tube proper, particularly the of its construction, the primary cause of a limitation in the operating energy of the apparatus, and is practically operative at such limited energy as to materially reduce the eiTectiveness, of the apparatus as a whole.

'I'he present invention has therefore for its primary object the production oi' an X-ray tube in which the anode is formed for a materially increased target or focal spot area. and in which the tube may be subjected to a continuous and effective heat kdissipation under an operating energy far exceeding that possible with present type apparatus.I i f A further object of the invention is to so mount and support the tube as to avoid any limit to the natural expansion and contraction of the tube, with a view to avoiding the great liability of tube damage incident to the present means for tube support.

A further object is the provision of means for effective heat exchange with the anode for complete cooling purposes, together with means whereby the cooling medium is insulated from the high-potential energy and is maintained at ground potential.

A further object is the provision of an insulat- -ing medium circulated through the apparatus externally of the tube proper, andserving to completely insulate the parts of the apparatus,

assist in cooling the parts, and prevent coronal discharge within the apparatus. 'I'he invention in the preferred form of details is illustrated in the accompanying drawings, in

which:-

Fig. 1 is a view in elevation, partly in section of the improved apparatus. f

' of the postV 4;

Fig. 2 is `a section on line 2-2 of Fig. 1.

Fig. 3 isa sectional detail, showing the mounting of the anode end oi' the tu/be proper. Fig. 4 is a section on line 4 4 of Fig. 1.. Fig. 5 is a sectional view of a detail, showing '5' the mounting of one end of the tube proper.

Fig. 6 is a bro en elevation, partly in section, mounting in the tube proper.

The improved apparatus comprises what may be termed a casing I, preferably constructed of 10 one or more layers o1' metal in hollow cylindrical form, havin'g an opening for the introduction of the various parts of the apparatus, with such opening hermetically sealed by a door 2.

3 and 4 pass through the wall 15 proper. The post 3 is provided with a central 20 tube 8, connected with the connector G, and forming a conduit for the leads 9 and I0 for the cathode circuit; the post 4 having a central rod II connected with the connector 1 for current Y passage, and also forming a support for the Special carrier for the anode end of the X-ray tube. f

The X-ray tube proper is, aside from the details hereinafter noted, of conventional form, as indicated at I2. The anode stem I3 y cylinder carrying a button I4, of tungsten or other suitable metal tol provide the target or focal spot. The opposite end of the anode stem I3 extends beyond the end of the wall 'of the tube proper, the latter being of course sealed to the anode stem, and the extended end of the anode stem is closed, except for the cooling medium pipes. The end of the anode stem is formed as a rectangular extension I5, providing the sup-- porting extension for theanode end of the X-ray '40 tube. 'I'he opposite end of the X-ray tube proper can'ies the conventional type of cathode I6. The cathode end of the tube proper is formed as a threaded extension I1, to receive a cap I8, havine.' a tubular extension cathode end of the tube.

A supporting section 20 of conducting materialis carried, preferably through threaded connection, by the lower end of the conductor rod II This supporting section is formed with a. transverse opening 2I,'in.which the rectangular extension I5 of the anode end of the tube is slidably supported. A guiding support is vgiven the extension by ball members 22, seating in is a hollow 3U i 9, for supporting the 45' `having bearing contact on the anode-stem extension I5 through springs 23 tensioned by plates porting section 20. vA conductor 25, fixed in the extension I 5, and to the section .20, together with the ball contacts 22 provide circuiting continuity.

The tube 8 in post 3 is terminally threaded to receive a right-angled support 26, the vertically depending portion of which is` formed with an opening 21 to receive the extension I9 of the cap I8, a' set screw 28 fixing theconnection. The leads 9 and I0 of the cathodevcircuit pass through the extension I9 for the usual cathode energization.

The invention contemplates the cooling and insulation of the anode stem, and to this end provides for the circulation of a heat-exchange medium, which is subjected to a continuous cooling beyond the casing. The medium employed is oil of high di-electric strength, and the means employed consists of'insulating tubes 29 and 38 fixed in and opening beyond the casing I, the lower ends of which tubes, arranged on a plane with the X-ray tube, are connected by flexible couplings 3|, spectively. The tube section 32, forming the inlet for the cooling medium, extends through the end of the anode stem I3, being sealed therein, and toward and terminating a short distance from the targetend of such stern. The tube section 33, forming the outlet of the cooling medium, is sealed in the closed end of the anode stem, being open, however, to the interior ,of the anode.

Beyond the casing I, the cooling medium circulatory connections are arranged as pipes, flexible if desired, such as 34 and 35, are connected to and in open communication with the insulating tubes 29 and 30, respectively, the pipe 34 leading to and through a filter 36, having a pressure-regulating by-pass 31, and beyond the filter, through a suitably driven pump 38, and to and through a coil 39 to which the pipe 35 is connected. The coil 39 is arranged in a cooling chamber 40, through which a cooling medium, as water, is controllably circulated.

Inaddition to the cooling medium circulated through the anode of the X-ray tube, there is provision for cooling and insulation of the parts within the casing external to the X-ray tube proper. The cooling medium here preferred is transformer oil of high di-electric strength, admitted to the casing I through pipe-4I, opening through the lower portion of the casing, and exhausted from casing through pipe 42, open to the casing at a point above the center of the casing.

The outlet pipe 42 leads through a coil 43 in a water cooled chamber 44, and from saidcoil through a filter 45 and a pump 46 to and through the inlet pipe 4I. The cooling and insulating medium controlled by this particular systemv is designed to comple/tely lill the casing I, and be continuously ci'. zulated, and incidentally cooled beyond such casing. In continued use of this medium more or less carbonization will occur, lowering he insulating effect, but the external filtering removes such carbon particles and maintains the high insulating efliciency of the medium.

The heretofore proposed X-ray tubes oper- A ated in conventional holders, which have parts at ground potential in the vicinity of the X-ray tube, or which have metallic parts within the high potential leads of the holders, tend to a certain coronal discharge, which not 'infrequently causes fracture or puncture` of the- X-ray tube. The `specific provision of the cooling medium above with tube sections 32 and 33, re-

described, coupled with the absence of metallic parts within the high potential neld, and depending upon the complete immersion of the parts in a constantly-circulated, artificially-cooled medium, will maintain effective cooling, prevent coronal discharge from the wall of the X-ray tube,

or from other parts within the high voltage circuit, will insulate the walls of the X-ray tube from the wall of the casing, and will prevent breakdown incident to carbonization of the medium.

The casing I is provided with the usual filter opening 41for the exit of the X-rays, the filter of course providing a hermetic seal for the opening.

X-ray tubes, as previously known, when operated at voltages of two hundred kilo-volts, limit the milliamperage through the tube to fifty milliamperes for short intervals, and not over thirty milliamperes for limits the filter thickness and the distance from the anode to the skin surface, preventing the use of thicker and denser filters desirable, for

example, in X-ray therapy of cancer, particularly cancer at a depth below the skin surface, by reason of length of time required. Furthermore, it is often desired to increase the target skin distance over the present limitation, in order to increase thedepth dose as compared with the skin dose. Here again the time limit is the deciding factor. With the present materially enlarged target area, the effective cooling of the anode stem, and of the external parts, provides an X-ray tube capable of much greater voltagev application and milliarnperage through the tube, without liability of tube damage. Thus the use of heavy or dense filters and increased target-skin distance is readily permissible without the timelimit handicap.

The anode stem I3 is a hollow cylinder having' a comparatively large diameter, and the cooling medium pipes are of such sectional area as will insure active and large heat-exchange with the cooling medium, that is the flow of such medium will be sufficient to greatly increase the heat dissipation as compared with previous cooling effects for X-ray tubes. This also permits greatly increased energy capacity for the tube, and thus materially increases the eiilciency of the tube for those eiects previously possible only at practically prohibitive time expense.

What is claimed as new, is:-

. 1. An X-ray apparatus including a casing, an X-ray tube therein, conductor posts secured in the casing and supporting the tube, one end of the tube being formed with a cylindrical hollow extension, an element carried by thepost to receive the extension, means carried by the element for fixing the extension with respect to the element, said hollow extension forming a conduit for the conducting wires, the opposite end of the tube having a rectangular extension, a conductingelement carried by the remaining post, said element being formed with an opening to receive the rectangular extension of the X-ray tube, and ball elements for guiding the extension and providing electrical continuity.

2. In an X-ray apparatus, a casing, an X-ray tube therein including an anode, an external source of dielectric oil, conduits intermediate said source and the interior of the anode, said conduits passing through the casing and delivering said oil immediately adjacent the target oi the longer periods of time. This source of oil supply, and means for; connecting said second source in circulatory relation to the interior of the casing, said conduits being in part of insulating material exteriorly, protected against breaking down by said oil circulated through the interior of the casing.

3. In an X-ray apparatus, a casing, an X-ray t'ube therein including an anode, an external source of dielectric oil, conduits intermediate said source and the interior of the anode, said conduits passing through the casing and delivering said oil immediately adjacent the target and extracting the oil from the end of the anode, a second source of oil supply, and means for connecting said second source in circulatory relation to the interior o! the casing, said conduits being in part of insulating material protected against breaking down by said oil circulated through the interior ofthe casing, and a iilter for said second source of oil arranged beyond the casing.

4. In an X-ray apparatus, a casing, a cooling system external "of said casing, an X-ray tube within the casing, circulating connections leading through the casing for directing dielectric oil for cooling and insulating the anode of the tube, said oil being maintained at ground potential, said circulating connections being in part of insulating material to prevent the high potential of the tube from charging the cooling system beyond the casing, said circulating connections being in ilexible connection with the tube, whereby to permit independent movement of the tube under expansion and contraction without interfering with the oil circulation.

5. In an X-ray. apparatus, a casing, an X-ray tube within the casing. circulating connections for directing a dielectric oil of ground potential to the anode of the tube, said circulating connections leading from a source beyond the casing to and through the casing and including sections of insulating material to prevent the high potential of the tube charging the cooling system beyond the casing, andmeans for independently circulating a cooling oil within the casing exteriorly of the tube, said latter cooling oil surrounding and externally insulating the insulating sections of the circulating connections.

6. In an X-ray apparatus, a casing, an X-ray tube within the casing, a conduit of insulating material flexibly connected to the tube for leading a dielectric oil into the anode of said X-ray tube, and means for providing for the discharge of the hot oil from the tube to and through the wall of the casing, said discharge means being in part of insulating material and preventing contact of the dielectric oil with'the external' or other portions of the walls of the X-ray tube. L

7. In an X-ray apparatus, a casing, an X-ray tube within thecasing and including an anode, means for circulating a dielectric oil from a point beyond the casing to and within the anode, said means including insulating sections carried -by and rigid with the casing to insulate said tube for reventin le p g ame of the high potential o! tube therein including an anode, a source of dielectric oil beyond the casing, tubes leading from the anode, said insulating sections being flexibly connected to the tube.

" `8. In an X-ray apparatus a casing, an X-ray tube'within the casing and including an anode, circulating connections for directing a dielectric oil from Xa source beyond the casing to and through the casing and to and within the anode, said connections includinginsulating parts to insulate the tube against high-potential leakage. and means for directing an independent circulating of a cooling agent within the casing externally of the X-ray tube and surrounding said insulating parts for external cooling and insulating thereof.

9. In an X-ray apparatus, a casing. im X-ray tube therein, insulated connector posts carried by the casing and supporting the tube, means for removably securing one end of the tube to one of said posts, a section removably carried by the other of said posts and formed with an opening, the cooperating end of the tube being formed with an extension corresponding in shape to that of the opening in the section and slidably iltting in said opening, said opening being without obstruction or resistance to the free movement of the cooperating end of the tube in both directions under expansion and contraction of the tube, and antifriction means carried by the section and bearing on the tube extension tting in the opening to facilitate movement vof the tube under expansion and contraction. A

1in). In an X-ray apparatus, a casing, an X-ray tube therein, insulated connector posts carriedby the casing and supporting the tube, Imeans for removably fixing 'the cathode end of the tube to one of said posts, means for mounting the anode end of the tube for free axial movement of the tube under expansion and contraction, cir- 'culatlng connections for a dielectric oil opening within the anode of the tube, and flexible connections in said circulation connections to permit axial movement of the tube under expansion and contraction without interfering with oil circulation."

Il. An X-ray apparatus including a casing, an X-ray tube therein, means for circulating a cooling iiuid within the casing exteriorly of said tube, an anode in said tube, circulating connections .for circulating a cooling uid within the anode, said connections being in part of insulating material for insulating the anode cooling system exteriorlyof the casing from the high anode potential, and said parts of insulating material being surrounded by the cooling fluid-circulated in the casing for insulating and cooling said parts.

12. In an X-ray apparatus, a casing, a tube within the casing including ananode, means leading from a source beyond the casing for circulating dielectric oil to, within, and from the anode, said means having flexible connection with 'the tube and rigid connection with the casing, said means insulating the casing from the high potential of the tube.

13. In an X-ray apparatus, a casing, a tube therein including an anode, circulating tubes leading from a. source of dielectric oil beyond the casing to and through the casing and to and from the anode, said tubes having ilexible sections to permit independent expansion and contraction of the X-ray tube and insulating sections to prevent the high potential of the X-ray tube from charging the casing and parts o! the circulatory sysf tem beyond the casing.

late the casing and source of dielectric oil beyond the casing from the high potentialv of the anode.

Y maar n. menons.

DiscLAl-M'ER 2,040,441.-Harry B. McEuen, Jacksonville, Fla. X-RAY AMA/Buys., Patent dated May 12, 1936. Disclaimer filed June 10, 1942, by the patentee. Hereby` eni'frs this disclaimer to claims 4 and 13 of said Letters Patent.

[O cial Gazette July 21, 1942.] 

